1. Field of the Invention
The present invention elates to diffusion devices and, more particularly, to droplet delivery devices capable of dispensing droplets of a predictable size for suspension or evaporation in an ambient environment.
2. Description of the Background of the Invention
A multitude of active material diffusion devices or diffusers exist in the marketplace. Many of such devices are passive devices that require only ambient air flow to disperse the liquid active material therein. Other devices are battery-powered or receive household power via a plug. A cord may be coupled between the plug and the device, or the plug may be mounted directly on the device.
Various means for dispensing active materials from diffusion devices are also known in the art. For example, some diffusion devices include a heating element for heating an active material to promote vaporization thereof. Other diffusion devices employ a fan to generate air flow to direct active material out of the diffusion device into the surrounding environment. In another type of diffusion device, active material may be emitted from the device using a bolus generator that develops a pulse of air to eject a scent ring. Still other diffusion devices utilize an ultrasonic transducer to break up an active material into droplets that are ejected from the device.
In one example, a diffusion device includes two heaters for dispersion of fragrances. The device includes a housing, a plug extending from the housing for insertion into an outlet, and two containers having fragrances therein and wicks extending therefrom to absorb fragrances from the containers. Each of the heaters is disposed adjacent one of the wicks to heat the respective wick to vaporize the fragrances therein. Optionally, a CPU controlled by internal software may first activate a first of the two heaters for a predetermined period of time. Once the period of time expires, the CPU deactivates the first heater and thereafter activates the second heater.
Other diffusion devices include a housing having a cavity for receiving a cartridge. The cartridge has a plurality of scent elements disposed on a rotatable disk. A blower is mounted in the housing to generate airflow by passing air across a scent element and out an aperture in the housing. The housing further includes rotating means that rotate the rotatable disk, thereby rotating the scent elements thereon. The device diffuses a first scent for a predetermined time period and thereafter rotates the disk such that a second scent is disposed in the airflow and the second scent is diffused for the predetermined time period. This process repeats for the remaining scents until the last scent element is diffused for a time period and then the disk is rotated to a home position.
Vibratory-type liquid atomization devices are described in Helf et al. U.S. Pat. No. 6,293,474, Martin et al. U.S. Pat. No. 6,341,732, Tomkins et al. U.S. Pat. No. 6,382,522, Martens, III et al. U.S. Pat. No. 6,450,419, Helf et al. U.S. Pat. No. 6,706,988, and Boticki et al. U.S. Pat. No. 6,843,430, all of which are assigned to the assignee of the present application and which are hereby incorporated by reference herein. These patents disclose devices comprising a piezoelectric actuating element coupled to a liquid atomization plate. The piezoelectric actuating element vibrates the liquid atomization plate in response to alternating electrical voltages applied to the actuating element. The vibration of the plate causes atomization of a liquid supplied by a liquid delivery system. An electrical circuit is provided to supply the alternating electrical voltages to conductive elements that are in electrical contact with opposite sides of the actuating element. The conductive elements may also serve to support the actuating element and the liquid atomization plate in a housing that contains the device.